A Spanaway man once convicted of salacious sex crimes involving an under-aged girl in Pierce County now is accused of trying to hire a 15-year-old girl for kinky sex in King County.

Prosecutors on Wednesday charged Stanley Scott Sadler, once known in local bondage circles as “Master Thorn,” with one count of attempted commercial sexual abuse of a minor.

Sadler, 57, is to be arraigned July 23 in Superior Court in Seattle. In the meantime, he’s being held in the King County Jail in lieu of $250,000 bail.

Seattle police began investigating him last week when a detective noticed an ad on a popular hook-up website. The poster was seeking a “young tight-bodied” female who was willing to have sex without birth control, according to a police report.

An undercover detective posing as a 15-year-old girl contacted the poster via email and offered to perform sex acts, including bondage, for $150, court records show.

“The conversations via email were of a graphic sexual nature, detailing the sex acts he was planning on doing to the 15-year-old minor female child in exchange for the $150 of U.S. currency,” the police report stated.

Sadler also sent a photo of a “dungeon” where the sex acts were to occur, the police report shows.

Detectives then made arrangements for Sadler to meet “the girl” in Federal Way about 12:15 p.m. Saturday. Seattle police were waiting and arrested him.

Sadler allegedly told the arresting officers, “I didn’t make any specific deals to do anything. I was just talking to her,” the police report states.

He later told investigators he planned to check the girl’s ID and that nothing sexual was going to occur if she was not of age, according to the report.

“If the person responding to the ad had been an actual 15-year-old girl, there is no doubt the defendant would have gone through with his sexual plans,” Carlstrom wrote in her pleading. “This defendant poses a significant danger to minor females …”

A Pierce County jury convicted Sadler in 2006 of sexually exploiting a 14-year-old girl who had advertised herself on the Internet as a willing sex partner who was 19.

He brought her home, had sex with her multiple times, encouraged her to have sex with another of his sexual partners and emailed sexually explicit photographs of her to friends.

Sadler was arrested after authorities were sent to his house to search for the girl, who’d been reported missing.

Pierce County prosecutors charged him with third-degree child rape, kidnapping and sexual exploitation of a minor, but he was convicted only on the exploitation charge and sentenced to 10 years in prison.

The Washington State Court of Appeals in 2008 tossed Sadler’s conviction and ordered a new trial, saying he did not get a fair one the first time.

He sat in prison until last year as prosecutors sought review of that decision. When that review did not come through, prosecutors dropped the charges against him.

Deputy prosecutor Michelle Hyer wrote in a May 2013 pleading that the alleged victim was not willing to testify and that Sadler already had served eight years, so trying him again seemed a waste “of the county’s scarce resources.”